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Species · Nebraska · BBS 2025 Release · 1966–2024

Double-crested Cormorant Population Trend in Nebraska

All statesWetland birds

Double-crested Cormorant in Nebraska has declined: down 49% on the route-weighted index since 1980.

-49%Since 1980TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
24Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
45YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Double-crested Cormorant Trends in NebraskaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Double-crested Cormorant in Nebraska. See the full index history below.

Double-crested Cormorant Population Forecast in Nebraska

If the recent trend holds, Double-crested Cormorant in Nebraska is projected to stay roughly flat through 2029, near 0.27 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±273%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.27Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.995% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±273%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Double-crested Cormorant in Nebraska is projected to stay roughly flat through 2029, near 0.27 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±273%, with 100% of held-out values landing inside the 95% band.19742029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.320.002.0
20260.300.002.0
20270.290.002.0
20280.280.002.0
20290.270.001.9

Double-crested Cormorant Survey Routes in Nebraska

Routes recording Double-crested Cormorant in Nebraska.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Kennedy1720171993
Piester Lake1420231974
Oglala Nat. Grass.1220192001
Crescent Lk1120141980
Johnson719881988
Crookston720192019
Sumner619971997
Almeria519921992
Kenesaw420022002
Arthur320232004
Paxton220161985
Brownlee220241995
Mullen220032001
Nenzel220212021
Agate 2120182018
Belvidere120222019
Seward120012001
Gretna120182007
Surprise120222022
Richland120041991
Swan Lake120211983
Gordon120162001
Murray Lake120111992
Wheeler Co120112011

Double-crested Cormorant Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.